package com.codeforces;

import java.util.Scanner;

public class _61A {

	static String a, b;
	static char[] ch;

	public static void main(String[] args) throws Exception {
		Scanner scanner = new Scanner(System.in);
		a = scanner.next();
		b = scanner.next();
		ch = new char[a.length()];
		for (int i=0;i<ch.length;++i) {
			if (a.charAt(i) == b.charAt(i)) {
				ch[i] = '0';
			}
			else {
				ch[i] = '1';
			}
			System.out.print(ch[i]);
		}
		System.out.println();
	}

}
